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Flashcards in Preventative Oncology Deck (8):

What is the metastatic cascade?

  • in situ ca
  • detachment
  • invasion
    • migration
    • protease secretion
  • intravasation
  • detachment from endothelium
  • circulation
  • reattachment
  • extravasation
  • invasion
    • migration
    • protease secretion
  • attachment
  • proliferation
  • distant mass


What are the risk factors of colon and rectal cancer?

  • Average risk: age >50
  • Increased risk:
    • adenomatous polyps/sessile serrated polyps
    • Prior CRC
    • smoking
  • Genetics:
    • positive family history of CRC
    • Cancer family syndromes
    • Lynch syndrome (aka, hereditary nonpolyposis colorectal cancer; HNPCC): defect in DNA mismatch repair enzymes
    • familial adenomatous polyposis: mutated APC gene
  • Inflammatory bowel disease: ulcerative colitis or Crohn’s disease


What are the screening modalities for colorectal cancer?

  • fecal occult blood test (FOBT)
  • Colonoscopy
  • Sigmoidoscopy/FOBT
  • Stool DNA testing (research)
  • Virtual colonoscopy (research)
  • Measure carcinogenesis itself (research)


What are some modalities for CRC risk reduction?

  • Smoking cessation
  • Diet and lifestyle
  • NSAIDs:
    • aspirin (COX1/2): risks outweigh benefits
    • celecoxib (COX2): APC patients
    • Vitamin D3 and Calcium
  • Increased screening/early detection


What is the role of chemoprevention in colorectal cancer?

  • Chemoprevention is the use of specific chemical, compounds to prevent, inhibit or reverse carcinogenesis
  • Chemoprevention represents the corner stone of primary prevention
  • Challenge: Required to have minimal toxicity because used for long periods in healthy people
  • Risk versus benefit


What is familial adenomatous polyposis? What is the standard treatment?

  • FAP: 100’s of adenomas occur in colon , rectum (<1% colorectal cancers)
    • Treatment: colectomy with ileorectal anastomosis
    • Sulindac: NSAID, causes regression adenomas in retained rectal segment.
      • 22 FAP pts randomized to placebo versus sulindac for 6 month.
      • 44% decrease in no.,  35% in mean diameter from baseline.
    • A subsequent prospective cohort confirmed long term use of sulindac in FAP
      • 76%  reduction at 1 year, sustained ( 74%) through 63 months of follow up


What is the effect of celecoxib in FAD?

  • A double blind placebo controlled trial, celecoxib, selective COX-2inhibitor, in FAP, for 6 months
  • In the  high dose arm, 28% reduction in number of polyps compared to placebo(4.5%)
  • FDA approved celecoxib as adjunct therapy FAP, only chemopreventive agent approved to date


What is the role of aspirin in prevention of colorectal adenomas?

  • Aspirin decreases the risk of adenomas compared to placebo
    • 81 mg is the most effective dose, especially in advanced lesions
  • USPSTF reccomendation is against using aspirin as prevention, but may be useful for more advanced cases